Problem: $ \left(\dfrac{4}{9}\right)^{-\frac{5}{2}}$
Explanation: $= \left(\dfrac{9}{4}\right)^{\frac{5}{2}}$ $= \left(\left(\dfrac{9}{4}\right)^{\frac{1}{2}}\right)^{5}$ To simplify $\left(\dfrac{9}{4}\right)^{\frac{1}{2}}$ , figure out what goes in the blank: $\left(? \right)^{2}=\dfrac{9}{4}$ To simplify $\left(\dfrac{9}{4}\right)^{\frac{1}{2}}$ , figure out what goes in the blank: $\left({\dfrac{3}{2}}\right)^{2}=\dfrac{9}{4}$ so $ \left(\dfrac{9}{4}\right)^{\frac{1}{2}}=\dfrac{3}{2}$ So $\left(\dfrac{9}{4}\right)^{\frac{5}{2}}=\left(\left(\dfrac{9}{4}\right)^{\frac{1}{2}}\right)^{5}=\left(\dfrac{3}{2}\right)^{5}$ $= \left(\dfrac{3}{2}\right)\cdot\left(\dfrac{3}{2}\right)\cdot \left(\dfrac{3}{2}\right)\cdot \left(\dfrac{3}{2}\right)\cdot \left(\dfrac{3}{2}\right)$ $= \dfrac{9}{4}\cdot\left(\dfrac{3}{2}\right)\cdot \left(\dfrac{3}{2}\right)\cdot \left(\dfrac{3}{2}\right)$ $= \dfrac{27}{8}\cdot\left(\dfrac{3}{2}\right)\cdot \left(\dfrac{3}{2}\right)$ $= \dfrac{81}{16}\cdot\left(\dfrac{3}{2}\right)$ $= \dfrac{243}{32}$